Salud Pública de México (Feb 2001)
Prevalencia de colonización por Moraxella catarrhalis en portadores asintomáticos menores de seis años Prevalence of Moraxella catarrhalis colonization in asymptomatic carriers under six years of age
Abstract
OBJETIVO: Determinar la prevalencia de colonización nasofaríngea por Moraxella catarrhalis en niños menores de seis años. MATERIAL Y MÉTODOS: Se realizó una encuesta, de enero a diciembre de 1998, en 604 niños de la ciudad de México, de entre dos meses y cinco años de edad, seleccionados mediante el marco muestral maestro y muestreo por conglomerados. Se tomaron muestras de exudado faríngeo, identificando M. catarrhalis. Se determinó la concentración mínima inhibitoria a diferentes antimicrobianos y detección de beta-lactamasas a través del método iodométrico. Para el análisis se utilizaron frecuencias simples, cálculo de razón de momios, intervalos de confianza al 95% y ji cuadrada de Mantel-Haenzel. Se consideró como estadísticamente significativo un valor de pOBJECTIVE: To determine the prevalence of upper respiratory tract colonization by Moraxella catarrhalis in children under six years of age. MATERIAL AND METHODS: A survey was conducted between January and December 1998 in Mexico City, among children aged 2 months to 5 years, selected through cluster sampling. Pharyngeal samples were taken for M. catarrhalis identification. The minimal inhibitory concentration to different antibiotics was obtained and beta-lactamases were determined by the iodometric test. Statistical analysis consisted of frequency distributions, odds ratios, 95% confidence intervals, and Mantel-Haenszel chi² . Statistical significance was set at p<0.05. RESULTS: After excluding 37 children, the study population was 604 children from Mexico City; M. catarrhalis was present in 130 pharyngeal specimens (22.9%). Most of the strains were positive for beta-lactamase production (75.4%). Eighty percent of the strains was resistant to penicillin and 70% to ampicillin and amoxicillin. None were resistant to cefotaxime, imipenem, meropenem and erythromycin. CONCLUSIONS: Prevalence of M. catarrhalis upper respiratory tract colonization is similar to that of other respiratory pathogens. These findings warrant future research on the role of M. catarrhalis as an etiologic agent in acute and chronic respiratory infections in Mexico. The English version of this paper is available at: http://www.insp.mx/salud/index.html
